The DNA Sequencing and Analysis Core has been in operation for the past twenty-one years and has provided CFAR members with state-of-the-art automated sequencing (DNA Sequencing Facility) and computer analysis capabilities (Molecular and Genetic Bioinformatics Facility). Core functions have included development of new methodologies for the automated sequencing process, training of investigators in the use of sequence analysis tools, development of new molecular biology approaches to characterize HIV/SIV genetic diversity, as well as supporting multidisciplinary and multi-institutional projects and collaborations. In the last budget period, the DNA Sequencing Facility has supported 62 CFAR investigators and provided essential services for over 100 AIDS related grants and contracts. 194 million base pairs of primary sequence were determined, generating over $2,100,000 in user charge-backs. Recently implemented automation has increased core efficiency and allowed to reduce user chargebacks from $8 to $6 per sequencing reaction. During the same time period, the Molecular and Genetic Bioinformatics Facility has actively supported over 30 CFAR investigators, and provided essential services for 62 AIDS related grants and contracts. Specific Aims of the Core are: 1. To continue to provide automated DNA sequencing capabilities to CFAR members through the availability and maintenance of dedicated Applied Biosystems DNA Sequencers with capillary electrophoresis systems. 2. To establish new methods, technologies and reagents to assist investigators in the characterization of HIV/SIV genetic diversity. 3. To provide and maintain a comprehensive set of modem bioinformatic databases and analytical tools for the analysis of genetic information, including gene and genomic sequences. 4. To provide technical support and training in the use of these bioinformatic resources.